I'm brand new to cosplaying and I'd really appreciate some help finding a wig for a character I want to cosplay! I will be dressing as Elsa from the upcoming Disney movie Frozen. I need a long, tousled, french braided wig that's white. Here's some reference pictures!

I thought the wig would be much easier to find than I have come to realize. I would prefer to find/ be linked to a pre-styled wig, but if anyone could help me to find even a cheap (the most I want to pay is $50) wig that I could style this way myself, I would be willing to try it!

Since the movie is so new, you are going to be hard-pressed finding one pre-styled and I have never seen a wig similar to it online before(sorry!) so I think you're going to have to try styling it yourself. This wig would probably suit your needs quite well- http://www.epiccosplay.com/40-natura...splay-wig.html
The nice thing about Epic Cosplay wigs is that they are very silky and don't tangle easily. That does mean it's a little more difficult to style it with product, but not impossible by any means.

You can also take a look at Arda wigs, but I browsed and couldn't find one that could work very well. The nice thing about Arda wigs is that they style very well and are easy to work with in that respect. The downside is they tangle worse than some of my eBay wigs! So basically the polar opposite of Epic Cosplay. If you don't mind straightening one of their curly wigs you might be able to use it!

Another site you CAN look on is Five Wits, but I warn you that sometimes their long wigs don't look as good in person(most of them are okay but there are a few that I was horrified by!) so you might want to look up reviews for a specific wig via google before buying it. They also style extremely well but tangle.

Finally, it looks like that specific style is going to be extraordinarilly difficult without a lace front wig so you can pull the hair away from your forehead without fear of revealing the cap. Unfortunately, those are also extremely expensive, definitely over $50. So you might have to either carefully modify the cap so it won't show or simply sacrifice some accuracy for the sake of looking good. I'm sure you can find tutorials if you google it though.

No problem!
If you can't find what you are looking for at Arda, I don't think Epic Cosplay will be impossibly difficult to style, you might just need spiking glue instead of hairspray.

Oh yes, and CosMonde on eBay makes fantastic wigs as well! So does Coszone. You might want to look them up. They mostly do character-specific wigs but with a bit of searching you may find something you like better!